I am a newbie to this forum even though I have used GIMP for a few years, but only on a PC running Ubuntu Linux. I had no problems till I changed to a Mac and now I cannot get a fine line without a lot of coarse pixelation/spatter on the 1 - 5 pixel wide round and fuzzy brushes. This is a problem as I use GIMP for illustration, mostly fine pencil and watercolour effects.
I recently upgraded from an old MacBook to a Mac mini running Lion, but the problem is still there.
Does anybody have any suggestions?